.container{
  position: relative;
  display: inline-block;
  vertical-align: middle;
  width: 200px;
  height: 200px;
  margin-right: 20px;
  .mask{
    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    z-index: 99;
  }
  img {
    width: 100%;
    height: 100%;
  }
}